Regulating-rheostat.



F. D. HALLOCK.

REGULATING RHEOSTAT.

APPLICATION FILED Luna, 1910 Patented May 24, 1910.

2 SHBETB-SHEET 1.

INVENTOR. mm

AT TORNEY WITNESSES 3 ANDREW B. GRAHAM co PHUTOJJTNOGNAFHERS, wisnmsmN.D. Q

F. D. HAL-LOOK.

REGULATING RHEOSTAT.

APPLICATXQN FILED JAR.3,1910. 958 806. Patented May 24, 1910.

2 SHEETS-SHEET 2.

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UNITED STATES PATENT OFFICE.

FLETCHER D. HALLOCK, 0F PITTSBURG, PENNSYLVANIA, ASSIGNOR TOWESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OFPENNSYLVANIA.

REGULATING-RI-IEOSTAT.

Specification of Letters Patent.

Patented May 24., 1910.

Application filed January 3, 1910. Serial No. 536,055.

To all whom it may concern:

Be it known that I, FLETCHER D. HAL- LOOK, a citizen of the UnitedStates, and a resident of Pittsburg, in the county of Allegheny andState of Pennsylvania, have invented a new and useful Improvement inRegulating-Rheostats, of which the following is a specification.

My invention relates to electric circuit controllers and it has specialreference to such rheostatic controllers as are adapted for regulatingboth the armature and field resistances for electric motors.

The object of my invention isto provide a simple and durable rheostat ofthe class above indicated by means of which either the armatureresistance or the field resistance of a shunt or compound wound motormay be regulated as deslred.

Motor starters have heretofore been constructed by means of which thearmature resistance of a motor may be gradually cut out and afterwardthe resistance in the field circuit adjusted as desired, but it isfrequently desirable to utilize the armature resistance for speedregulations in addition to the usual field regulation.

According to my present invention, I provide a regulating rheostat whichnot only combines the desirable features outlined above but is also soarranged as to automatically return to its off position if the motorcircuit is interrupted.

Figure 1 of the accompanying drawings is a plan view and Fig. 2 is apartially sectional elevation of a regulating rheostat constructed inaccordance with my invention. Fig. 3 is a diagram of the circuitconnections for the rheostat of the other figures.

Referring to the drawings, the structure here shown comprises astationary slab or base 1 of insulating material to which a series ofarmature-resistance contact members 2 and field-resistance contactmembers 3 are secured and are arranged substantially in concentric arcs:contact-bearing arms 4 and 5, a retracting spring 6, and anelectro-magnet 7 for accentuating various armatureregulating positionswhich the device is adapted to occupy. The arms 4 and 5 are rotatablysupported on a post 8, the arm 5 being adjacent to the base or slab land the arm 4 being mounted adjacent to the arm 5. The arm 4 isbifurcated at its inner end and a helical retracting spring 6 is coiledabout a collar 9, which is mounted on the post 8, between the arms ofthe lever. The outer end of the spring 6 is bent inwardly and projectsthrough a slot 10 in the outer end of the post 8 and the inner end ofthe spring is bent outwardly and engages a notch 11 in the inner end ofa rib 12 with which the arm 5 is provided. From the foregoing, it isevident that the arm 4 is free to rotate about the post 8 as an axiswhile the arm 5 always tends to occupy its ofi position in which itengages a stop 13.

The arm 4 is provided with contact fingers l4 and 15 which arerespectively adapted to engage the contact members 2 and 3. The arm 5 isprovided with a contact finger 16 which is adapted to short circuit thearmature resistance by engaging the contact member 17 when the armengages the stop 18 and it is adapted to engage a contact ring segment19 when the arm occupies an inter1nediate position. The rib 12 of thearm 5 is provided with a notch 20 at its outer end in which a roller 21,which is rotatably mounted on a pin 22, is disposed.

The outer end of the arm 4 is provided with a narrow slot 23 which isparallel to the plane of the base 1 and in which a latch 24 is located.The latch 24 is secured to a pin 25 and is adapted to engage the roller21 at the outer end of the arm 5 whenever it is desired to operate thearms together, a helical spring 26, which is located in a hole 27 at theouter end of the arm 4, being adapted to prevent the latch from beingaccidentally released. The pin 25 is rotatably supported at the outerend of the arm 4 and extends outwardly therefrom to receive a handle 28,which is also secured to it. The arrangement of parts is such that thelatch 24 may be released by suitably rotating the handle 28. The samehandle is utilized for adjusting the arms 4 and 5 together and for adjusting the arm 4 independently.

The inner end of the arm 5 is enlarged to' constitute a segmental diskprojection 29 and a ring segment 30 is secured to its circumferentialsurface by means of screws 31. The ring segment 30 is provided with aseries of counter-sunk holes 32 which are engaged by a ball 33 when theelectro-magnet 7 is energized, as hereinafter pointed out. The structureof the electro-magnet forms no part of my present invention, but Iprefer to employ an arrangement similar to that 110 shown and describedin my co-pending application, Serial No. 437,324, filed June 8, 1908.

A quick-break switch 34 is preferably provided for the purpose ofinterrupting the circuit in order that an arc may not be formed when thecontact fingers 14 and 15 are separated from the contact members 2 and3, in passing to the off position of the controller.

The operation of and the circuit connections for the device are asfollows :-Assuming that the arms 4 and 5 are latched together and thatthe controller occupies its off position, if the arms are moved in aclockwise direction from engagement with the stop 13, contact member 16is first brought into engagement with the contact ring segment 19. Atthis point two circuits are established as follows one from lineconductor 40 through arm 5, finger 16, magnet 7 and resistance 41 toline conductor 42; and another from finger 16 through contact 19,conductor 43 and motor field magnet winding 44 to conductor 42. Thecontact members 14 and 15 next come into engagement with the first ofthe series of the contact members 2 and 3 and the motor armature circuitis completed from conductor 40 through arm 4, finger 14, contact 2,resistance 45 and motor armature 46 to conductor 42. The fieldresistance is short circuited by the engagement of the contact members16 and 19 and the armature resistance is thus entirely included in thecircuit. As the arms are still further rotated in the same direction,the armature resistance is gradually cut-out by the engagement of thearm 14 with successive contact members 2 which are connected tointermediate points of the armature resistance, in the usual manner.When the contact arms finally reach their extreme position in thisdirection, the arm 5 comes into engagement with the stop 18 and thecontact member 16, by engaging the contact member 17 short circuits thearmature resistance and interrupts the shortcircuit which formerlyexisted to the field resistance, as shown in Fig. 3. hen the motorcircuit is first completed, the electromagnet 7 is energized as aboveindicated so that the various positions of the arms are accentuated byengagement of the ball 33 with the counter sunk holes 32. The forceexerted by the electro-magnet is sufficient to overcome the retractingeffort of the spring 6 and, consequently, the arms may be left in anyintermediate position for the purpose of obtaining speed regulation bymeans of the armature resistance. The holes 32 correspond in position tothe stationary contacts 2 in order that the finger 14 may squarelyengage one of the contacts in any intermediate position of the arm.

If the arm 5 occupies the position shown in Fig. 1 of the drawings andthe contact member 16 engages the contact member 17, the speed of themotor may be increased by slightly rotating the handle 28 to release thelatch 24 from the roller 21 after which the arm 4 may be moved in acounter-clockwise direction so that the contact members 14 and 15 sweepback over the contact members 2 and 3 in reverse order. The frictionbetween the contact members is sutlicient to hold the arm 4 in anyintermediate position unless the electro-magnet 7 becomes deenergized byreason of the interruption of the motor supply circuit or a materialreduction in its voltage. Under these conditions, the arm 5 will bereleased and the spring 6 will return both arms to the ofi' position sothat the motor windings will not be injured if full line voltage isagain applied. As soon as the contact member 16 engages the contactmember 17, the contact finger 14 is inactive and the contact finger 15serves to regulate the resistance in the field circuit of the motor.

If it is desired to operate the motor at a very high speed, both armswill be rotated from the off position into engagement with the stop 18and the arm 4 will then be released from the arm 5 and will be rotatedin the opposite direction until a projection 35 engages one end of therib 12. WVhen the arms are released and are retracted to the offposition, a pin 86, which extends inwardly at right angles to anextension 37 of the arm 4, actuates the quickbreak device 34 tointerrupt the motor circuit.

The size and arrangement of parts of the device shown, may bemodifiedwithout departing from the spirit of my invention, and I desirethat only such limitations shall be imposed as are indicated in theappended claims.

I claim as my invention:

1. A controller for electric motors comprising a pair of contact-bearingarms, means for retracting one of the arms to its oif position, meansfor latching the two arms together and a handle for operating both armstogether and for releasing one of the arms and operating it separately.

2. In a controller for electric motors, the combination with a pair ofcontact-bearing arms, means for latching the two arms together, aretracting spring acting upon one of said arms for returning both ofthem to their off position, electro-magnetic means for opposing theaction of the spring and manually operated means for releasing thesecond arm, whereby it is permitted to operate independently of thefirst.

3. A controller for electric motors comprising a pair of contact-bearingarms one of which is adapted to successively short circuit the motorfield and the motor armature resistances as it progresses in one (11-subscribed my name this 24th day of Dec, rection and the other of whichis adapted 1909. to radually exclude the armature resistance as itprogresses in one direction and to I FLETCHER HALLOCK 5 graduallylnterpose the field resistance as it Witnesses:

progresses in the opposite direction. ALBERT VAN ZANDT,

In testimony whereof, I have hereunto B. B. HINES.

